Heat exchangers for heat exchange between at least a first heat exchange fluid and a second heat exchange fluid are used in many different kinds of applications and processes, such as offshore oil platforms, steam condensate systems and fertilizer plants, to name a few. A heat exchanger may be used for many different purposes such as e.g. cooling and heating fluids, condensing gases, and evaporating liquids.
In some applications pressure pulses may occur in a heat exchange fluid. For instance, pressure pulses may occur in applications were one heat exchange fluid is a liquid in which slugs of gas may occur. For instance, on offshore oil platforms wet crude oil which contains oil, water, and fossil gas is extracted from a drill hole. The wet crude oil is heated in a heat exchanger for further processing. The fossil gas forms slugs in a conduit flowed through by the wet crude oil. A gas slug reaching the heat exchanger is followed by liquid (i.e. oil and water) which will enter the heat exchanger at high speed and cause a sharp pressure pulse which may damage the heat exchanger. Heat transfer elements may be damaged, gaskets may be blown. A different example of a heat exchange fluid containing gas is condensate or other liquid at a temperature close to the boiling point of the condensate/liquid. When such a condensate/liquid flows at high speed through a conduit, the pressure in the condensate/liquid may be reduced causing the condensate/liquid to boil and thus forming gas. A heat exchanger at an end of such a conduit will be subjected to pressure pulses for the same reason as explained above in connection with offshore oil drilling but also due to the gas expanding in the conduit pushing condensate/liquid ahead of the gas at high speed into the heat exchanger. Again, the heat exchanger may be damaged from such pressure pulses.
JP 55014468 suggests the use of a safety valve or a rupture disc connected to conduit at an inlet side of a condenser. When a pressure pulse occurs, the safety valve or the rupture disc opens a connection between the conduit at the inlet side of a condenser and a conduit at an outlet side of the condenser.
JP 52120445 suggests a bypass conduit between an inlet side and an outlet side of a condenser. In the bypass conduit a valve is arranged.
Although a condenser may be spared from a pressure pulses in the two above mentioned arrangements, the pressure pulse is not damped and equipment downstream of the condenser may be damaged by a pressure pulse.
JP 06-313566 discloses an air separator for water hammer prevention to be arranged in a domestic warm water system. The air separator comprises a main part forming a chamber with a water inlet leading to the chamber and an outlet leading from the chamber. Inside the chamber an air layer is formed and an air vent valve is arranged for venting air from the chamber. The air separator is arranged in an outlet conduit leading from a water heater to a radiator or water tap and thus relies on the water flowing through the chamber in order to absorb water hammering.